The invention relates in general to rocket engines and in particular to a new and useful rocket engine having an insulating layer on the outer circumference of its propellant charge and/or the inner side of the combustion chamber casing of a rocket engine and to a method of producing the insulating layer.
The propellant insulating layer of ramjet rockets is intended to heat insulate the propellant charge against heating by the air friction of the rocket in order to prevent impairment of the burnoff and hence of the compressive work range of the propellant charge, and also is intended to protect the combustion chamber casing from too great a heating by the combustion gases. Since with increasing thickness of the propellant insulating layer the diameter of the propellant charge and hence the range of the rocket is reduced, another desideratum is to meet the named requirements by as thin as possible an insulating layer.
It is known practice to produce the propellant insulating layer of plastic, e.g. polybutadiene (German No. OS 27 58 814). However, as the plastic melts and decomposes in the presence of the combustion gases, heating of the combustion chamber casing to high temperatures is not prevented thereby. Also it has been proposed to incorporate the inorganic materials, such as alkali silicates, into the plastic to increase the heat transmission resistance of the insulating layer to the combustion gases (U.S. Pat. No. 3,916,618). As the plastic matrix melts and decomposes quickly nevertheless, the effect achieved thereby is very slight, however.